根据Java中的一个文件对两个文件进行排序

Question

我的Java课程中有一个最终作业。我不理解，老师吹。请帮忙！！ 这是作业：

我无法通过GPA进行排序，就像作业所说它需要采用GPA序列一样。

这是第一个文件：

5
Aaron
Smith
4
Dallas
Lambert
3
Mike
Scott
2
George
Mcfly
1
Greg
Peterson

这是第二个文件：

1
4
3.2
2
5
2.2
3
6
3.0
4
3
4.0
5
2
3.5

请注意，两个文件中的第一个数据元素是学生编号。

这是我的程序代码：

 public static void main(String[] args) throws FileNotFoundException, IOException {
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter first file name: ");
        String firstFile = "/Volumes/Sandisk/Personal/" + scanner.next();
        File file = new File(firstFile);
        FileReader fileReader = new FileReader(firstFile);
        BufferedReader buffReader = new BufferedReader(fileReader);

        //Second File input
        Scanner scannerTwo = new Scanner(System.in);
        System.out.print("Enter second file name: ");
        String secondFile = "/Volumes/Sandisk/Personal/" + scannerTwo.next();
        File fileTwo = new File(secondFile);
        FileReader fileReaderTwo = new FileReader(secondFile);
        BufferedReader buffReaderTwo = new BufferedReader(fileReaderTwo);

        int studentNum;
        int studentNumTwo;
        String name;
        String lname;
        int classHour;
        double grade;
        int index = 0;
        int indexTwo = 0;
        double GPA;
        double points;
        String letterGrade;

        //arrays
        int[] studentNumArray = new int[20];
        int[] studentNumTwoArray = new int[20];
        String[] nameArray = new String[20];
        String[] lnameArray = new String[20];
        int[] classHourArray = new int[20];
        double[] gradeArray = new double[20];
        double[] GPAArray = new double[20];
        String[] letterGradeArray = new String[20];

        //first file
        for (String numParse = buffReader.readLine(); numParse != null; numParse = buffReader.readLine()) {

            studentNum = Integer.parseInt(numParse);

            studentNumArray[index] = studentNum;

            name = buffReader.readLine();
            nameArray[index] = name;

            lname = buffReader.readLine();
            lnameArray[index] = lname;

            index++;
        }

        //read file 2
        for (String numTwoParse = buffReaderTwo.readLine(); numTwoParse != null; numTwoParse = buffReaderTwo.readLine()) {

            studentNumTwo = Integer.parseInt(numTwoParse);
            studentNumTwoArray[indexTwo] = studentNumTwo;

            String classParse = buffReaderTwo.readLine();
            classHour = Integer.parseInt(classParse);
            classHourArray[indexTwo] = classHour;

            String gradeParse = buffReaderTwo.readLine();
            grade = Double.parseDouble(gradeParse);
            gradeArray[indexTwo] = grade;

            //GPA
            points = grade * classHour;
            GPA = points / classHour;
            GPAArray[indexTwo] = GPA;

            //Grade
            if(GPA >= 4.0){
                letterGrade="A";
                letterGradeArray[indexTwo]=letterGrade;
            }
            if (GPA < 4.0 && GPA >= 3.4) {
                letterGrade = "A";
                letterGradeArray[indexTwo] = letterGrade;
            }
            if (GPA < 3.4 && GPA >= 2.7) {
                letterGrade = "B";
                letterGradeArray[indexTwo] = letterGrade;
            }
            if (GPA < 2.7 && GPA >= 2.0) {
                letterGrade = "C";
                letterGradeArray[indexTwo] = letterGrade;
            }
            if (GPA < 2.0 && GPA >= 1.2) {
                letterGrade = "D";
                letterGradeArray[indexTwo] = letterGrade;
            }
            if (GPA < 1.2 && GPA >= 0.1) {
                letterGrade = "F";
                letterGradeArray[indexTwo] = letterGrade;
            }
            if (GPA < 0.1) {
                letterGrade = "NONE";
                letterGradeArray[indexTwo] = letterGrade;
            }

            indexTwo++;
        }

        //final sort by GPA
        double temp2;
        int length2 = GPAArray.length;
        for(int i = 0; i<length2; i++){
            for(int j =i+1; j<length2; j++){
                if(GPAArray[i]< GPAArray[j]){
                    temp2=GPAArray[i];
                    GPAArray[i]=GPAArray[j];
                    GPAArray[j]=temp2;

                    String temp6;
                    temp6=letterGradeArray[i];
                    letterGradeArray[i]=letterGradeArray[j];
                    letterGradeArray[j]=temp6;

                    int temp7;
                    temp7=studentNumTwoArray[i];
                    studentNumTwoArray[i]=studentNumTwoArray[j];
                    studentNumTwoArray[j]=temp7;

                    int temp3;
                    temp3=studentNumArray[i];
                    studentNumArray[i]=studentNumArray[j];
                    studentNumArray[j]=temp3;
                }  
            }
        }
        studentNumArray=studentNumTwoArray.clone();

        System.out.printf("%40s\n", "Student Report");
        System.out.printf("%-20s %10s %15s %15s\n", "Student Number", "Student Name", "GPA", "Grade");
        System.out.println("_______________________________________________________________________");

        for (int i = 0; i < studentNumArray.length; i++) {
            if (nameArray[i] != null) {
                System.out.printf("%-18d %-1s %-18s %-20.2f %-10s\n",
                        studentNumTwoArray[i], nameArray[i], lnameArray[i], GPAArray[i], letterGradeArray[i]);
            }
        }

    }

如果你愿意，请帮忙。